I made custom descriptions and biographies for my characters, edited their clothes color that would be, etc. I want to know if I can save those characters or overwrite the old ones as updated versions. I don't want to have to timelessly put it all back in by hand or anything like that. I don't mind doing it, but I'd like to know if there's a way to do this or not.

You can open save data in any text editor and edit it manually. If you use json parser you can get a clear picture on what to edit/replace on it. If your version is fairly recent it should work more or less smoothly, if not you'd have to be more cautious with your edits. Also I can recommend you feeding your save data to chatgpt asking it to work it out for you, can save you a lot of tedious work but you better back your saves up before editing them regardless.